Power supply



FIG. 1 is a perspective view of a power supply showing our new design;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a right side view thereof;

FIG. 5 is a left side view thereof;

FIG. 6 is a top view thereof; and,

FIG. 7 is bottom view thereof.

The broken line showing of various features of the power supply are for environmental purposes only and form no part of the claimed design. 

CLAIM The ornamental design for a power supply, as shown and described. 